Precooked meals do not cause tooth decay because they are typically processed and cooked in a way that eliminates or reduces the presence of sugars and carbohydrates, which are the main culprits for tooth decay. Additionally, prepackaged meals often do not contain sticky or chewy foods that can get stuck in between teeth and promote decay. However, it is important to note that maintaining good oral hygiene practices, such as regular brushing and flossing, is still necessary to prevent tooth decay and maintain overall dental health.